1. WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow,
U.K. G1 1XL
2. School of Chemistry, Newcastle University, Newcastle upon Tyne, U.K. NE1
7RU
3. Departamento de Quı́mica Orgánica e
Inorgánica-IUQOEM, Universidad de Oviedo-CSIC, E-33071 Oviedo, Spain